The invention relates to a wheel bearing unit with a wheel hub having a wheel flange with a cover provided for covering a side of the wheel flange facing away from the wheel, wherein the cover is fixed directly or indirectly on the outer ring and forms, together with the wheel flange, a labyrinth seal.
Such wheel bearing units were previously used to prevent disadvantageous effects of spray water on the seals of the wheel bearing unit. The cover can be mounted on a stationary outer ring of the wheel bearing and cover the wheel flange axially, wherein a labyrinth seal can be provided radially on the outside. In this way, the cover acts in combination with the surface of the wheel flange or with a labyrinth seal like a pre-seal that is mounted in front of the actual seal of the wheel bearing. The actual seal, also called main seal below, can be made from a cartridge seal and/or can have a sealing lip, wherein the sealing lip is in rubbing sealing contact. As an alternative to the cartridge seal, a carrier with a radial or axial sealing lip could also be provided.
From DE 10 2008 051 065 A1, a cover for a wheel bearing unit is disclosed that has a cylindrical fastening area, with which this can be mounted on the outer ring of the wheel bearing unit and partially forms, radially outside with a cylindrical projection, a labyrinth seal that is formed with a radial end of the wheel flange.
In this way, spray water is very effectively kept away from the vehicle-side inner side of the wheel flange, with which the main seal is exposed to significantly less spray way and foreign particles due to the pre-seal compared with conventional wheel bearing units. It is especially advantageous if the mentioned labyrinth seal is also partially formed by the brake arrangement.
Due to the ring-shaped construction of the cover, after the installation of the wheel bearing unit it is not possible to remove or insert bolts that are provided for fastening the rim from the flange or into the flange on the vehicle side, because this side of the wheel flange is covered by the cover and is thus not accessible.
Disassembly is also extremely problematic; in particular, for disassembly the wheel bearing must also be removed only to remove the cover. Because the separation of the wheel hub with the flange from the stationary part always involves the rolling space with the rolling bodies, this undertaking represents a disproportionately large expense.